


Tentacanthropy: Infection

by Shadow_of_Quill



Series: Tentacanthropy [1]
Category: Sherlock (TV)
Genre: Dubious Consent, M/M, Tentacles, tentacanthropy
Language: English
Status: Completed
Published: 2011-06-21
Updated: 2011-06-22
Packaged: 2017-10-20 14:58:46
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,808
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/213992
Author URL: https://archiveofourown.org/users/Shadow_of_Quill/pseuds/Shadow_of_Quill
Summary: <blockquote class="userstuff">
              <p>John has a secret. Like Sherlock said, there's always something he misses... and this time, John wishes that he'd kept missing it. But not for long.</p>
            </blockquote>





	1. John's POV

**Author's Note:**

> Originally written for one of the many Sherlock kinkmemes. I'm currently working on Sherlock's POV, which will be the second chapter.

John groaned a little louder than he meant to. Everything was so sensitive during this part of the cycle - not time, not quite, but so close that his skin was starting to feel elastic, switching between too tight and too loose, and he knew that touching himself was a bad idea right now, but he just needed some, a little -

"John?"

Sherlock's voice, sounding vaguely curious about the fact that his flatmate had barricaded himself in his room and was making unusual noises. John tried to clear his throat, tried to think of something to say, but he couldn't stop touching himself and all that came out was another groan, louder than the first one.

"John. Your behaviour over the last few days has been a distinct departure from your usual routines. Please explain why."

John glared at the door. Bloody Sherlock, with his always-being-right and his arrogance and his long fingers and his lithe movement and why the hell did his brain have to go on holiday _now_ , dammit, he hadn't managed to find anyone yet -

The door thumped. Sherlock was trying to get in. John could feel his body stirring at the thought, parts that normal people - normal _humans_ \- never had to worry about starting to twitch eagerly. Sherlock, pale skin and dark hair and pretending to be so cold, surely it would be worth it to make him seem alive, make him show interest in something other than some puzzle for once, make him see John as more than his partner(pet) and have something real show in his face -

"Don't!" John managed to shout, trying to force down the darkness rising in his thoughts. "Don't come in." Four words, and he was amazed that he got that many out, because he'd never tried to time his cycle when there was someone around who he was _interested_ in and what do you know? It had sped up drastically as soon as Sherlock started making it so obvious that he was close (close enough to grab, close enough to hold down and -)

"Don't be foolish, John." A careless rebuttal he'd heard far too often; of course Sherlock knew better than him.

Except this time, he didn't. And he was about to get that fact thrown in his face in the worst way possible.

John took a deep breath, trying to steady himself, and stretched. Arms, legs, and newly-extended tentacles all reached out.

The tentacles quickly reached into the pile of furniture in front of his door and sent it scattering, leaving nothing to hold the door closed as Sherlock tried - again - to break it open.

He fell into the room - literally - and any other time, John would probably have been trying not to laugh at him, but at that moment all that mattered was that he was in reach, _finally_ -

" _Homo Sapiens Tentaculigerous_. Of course," was Sherlock's only reaction as John's tentacles slid inside his clothes and burst the seams, leaving him naked and tightly wrapped. "During the fertile period of your biennial cycle, I see," he added as John tugged him over to the bed, barely hearing what he was saying. "Honestly, you could have done better than to - John? John? JOHN!"

John snapped back to something approaching sanity. "Sherlock," he panted, one of his tentacles starting to probe at Sherlock's anus, "you picked a really bad time to try and come in."

"Evidently." Sherlock wriggled slightly, managing to twist himself in a way that made John's tentacles loosen automatically. "Next time, you should mention this before I'm driven to try and knock your door down. And, please, ask. I believe it's considered polite to hold negotiations beforehand?"

"Ah," John was blushing furiously, and it wasn't all - or even mostly - because of the fact that he couldn't stop himself from molesting Sherlock even for long enough to get his permission (what if he said no?). It was because of the sheer amount of physical contact he had with Sherlock, with his _tentacles_ -

He'd heard others like him trying to describe how it felt to sense someone during this part of their cycle. Something like touch, and something like taste, and something that just didn't fit human terms enough to be explained.

Whatever it should be called, though, Sherlock felt/tasted/whatever _fantastic_. And then he rolled his eyes, and caught a handful of one of John's tentacles and rubbed it against his (half-hard, when did he start responding?) dick, and John made a noise that would have been truly embarrassing if he'd still been aware enough to _be_ embarrassed and yanked Sherlock down on top of him.

Sherlock had the temerity to smirk. "I've heard some -" John coiled one tentacle around Sherlock's dick and started squeezing gently, making him gasp - "truly fascinating stories about tentacle-sex during the fertile period, and I'm ex-" his voice actually broke as John carefully slid the tip of one tentacle inside him "-pecting this to be -" another tentacle came up to hover expectantly in front of his face - "- John?"

Normally, hearing Sherlock sound so worried would have stopped John - it already had, earlier - but Sherlock had more-or-less given his consent (he hadn't left, and if he could wriggle out of a full hold, he could leave if he really wanted to), and John was too caught up in what he was feeling to notice the buried panic in his voice. The tentacle pressed on Sherlock's lips as the first one slid deeper inside him and was joined by a second. John groaned with pleasure, head falling back, and tightened his grip on Sherlock. He hadn't done this for so long; he'd been taking hormone suppressants since before he went to Afghanistan, and he'd never have stopped if his regular supplier hadn't been killed while he was out of the country. He'd made himself forget just how good it was; how no one and nothing mattered but having (someone)Sherlock here with him, and _having_ (someone)Sherlock.

He forced his eyes open again, and looked up at Sherlock's face. The sight of those pale lips stretched around one of John's tentacles brought yet another groan from his throat, the two tentacles working their way into Sherlock's body from the other end spasming and surprising a muffled cry from his (mate)(victim)(prey)lover. John absently tightened his hold on Sherlock's dick in a complicated gesture that human fingers (or other body parts) could never hope to imitate. The cry changed tone, Sherlock's eyes half-closing. John smiled, twisting his tentacles together inside Sherlock and seeing him shudder in reaction. It wouldn't take much more. He pulled Sherlock into position, kneeling astride him, and shifted the tentacles inside him until there was enough room for him to _really_ fuck Sherlock, with more than just his tentacles.

Something in the back of his mind protested: he shouldn't, it's a bad - but the thought was lost, drowned under the feel/taste of Sherlock in his tentacles, Sherlock straddling him, Sherlock sinking down willingly onto his dick and moaning around the tentacle that still filled his mouth as John swore breathlessly. He'd never had a partner like this, he'd never had someone he wanted for them instead of just for being there and interested, he'd never had someone whose name he remembered even when he was so blissed out that he forgot -

forgot -

Sherlock cried out again, louder, tightening around John as he finally came, and John thrust up desperately and joined him.

John's tentacles slid out of Sherlock, heavy and limp, already harder to move. He just barely tugged Sherlock down to lie on top of him, where he could wrap him in his arms while his tentacles retreated into their usual places inside his body (coiled around his torso, between the upper muscle layer and his ribcage).

Sherlock stretched contentedly. "So. I assume that you have successfully infected me with tentacanthropy?"

John froze. Oh. Oh, _God_ , that was it, that was the thing he'd forgotten ( _how_ had he forgotten?); tentacles were fine, but _do not come inside someone else_. Not unless they've already got the same problem.

Sherlock raised an eyebrow at his horrified expression. "Honestly, John, don't tell me you didn't realise for yourself that it makes far more logical sense for the both of us to be infected. This way, there's no need to worry about Moriarty somehow arranging for your next pick-up to be one of his people, we can simply take care of each other. Much more efficient."

John stared at him. "You got yourself infected intentionally."

"Yes."

"By me."

"Yes."

"Because it's _logical_?"

"Obviously. Does sex usually have this unfortunate effect upon your intelligence?"

John let his head fall back against the mattress (he'd lost his pillow at some point). "For - you didn't even know I was a tentacanthrope! Did you?"

"Not until I saw the reason you'd hidden yourself away," Sherlock admitted huffily. "I fail to see what that has to do with anything, however."

John rubbed at his forehead, trying to soothe away the slowly-growing ache that came from trying to follow Sherlock's more bizarre leaps of thought. "Why?" he asked plaintively.

Sherlock raised himself on his arms, leaving most of his body still pressed against John's. "I told you," he said with exasperation. "It makes far more sense if we act as each other's mates, instead of you going off with other people chosen at random when your hormones overload your common sense."

(mates)

John blinked at him, instincts combining with the time he'd spent living with this man and adding up to - "You know, normal people just propose. Rings or something. Not, 'infect me so that it's more logical for us to be together'."

Sherlock snorted, flopping back down onto John. "Boring." He paused, raised his head far enough to see John's face, and added with a touch of uncertainty, "Do you want rings?"

John grinned at him ruefully, and shook his head. "I don't really think we need them by now, do we?" Sherlock looked relieved, and wriggled into a position that he apparently found more comfortable.

John rolled his eyes at the ceiling as Sherlock's knee dug into his thigh and his hand somehow wormed its way under John's uninjured shoulder. "Don't know why I'm surprised," he murmured, dropping into sleep in spite of himself, "you've never done anything normal..."

***

Sherlock spent the next four days seeming deathly ill as the tentacanthropy took firm hold. John made sure he ate enough to provide raw material for the developing tentacles, and tried not to cringe too obviously whenever he thought of Mycroft's likely reaction to what he'd done.

He hadn't expected the semi-sarcastic Congratulations! card, but, he thought wryly, he really should have. And binned it before Sherlock could get annoyed over it.

And, once Sherlock was over the transformation stage, nothing really changed in their lives. Well, not for the two years it took to find out that their mating cycles were concurrent...


	2. Sherlock's POV

**Notes for the Chapter:**

> It's hard to write porn from Sherlock's point-of-view (for me, at least) and I'm afraid this chapter came out as more of a character study. Still, I give you Sherlock's view of what happened.

Sherlock actually hesitated outside the door of John's bedroom. Not from any personal sense that his behaviour was inappropriate, but he knew that there was quite a strong possibility that John would see it differently.

A muffled groan sounded from inside the room. Sherlock nodded, convinced that if absolutely necessary he could claim concern (or curiousity, whichever John was more likely to believe) and tried to open the door.

It was blocked.

"John?" he asked, meaning 'Please move whatever is in the way so that I can come and see what you are doing'. The only response was another groan, so he continued, "John. Your behaviour over the last few days has been a distinct departure from your usual routines. Please explain why."

He waited, but there was no indication of any reaction from John. That was unacceptable. John always reacted to him. He looked more carefully at the door (not overly strong; should only need moderate force to open) and braced himself.

Clearly he'd made a miscalculation somewhere, as the door was still closed and his shoulder was bruised. He did, however, gain a reaction from John.

"Don't! Don't come in."

"Don't be foolish, John," Sherlock dismissed the warning. Of course he was going to come in; John was trying to hide something from him, and that was simply unacceptable. (He must have barricaded himself in, blocking the door with furniture; more force would be required.) It was possible that he'd need to build momentum by a short run, but he decided to try once more from a standing position before going to those lengths.

It was just as well he did, since John cleared the blockage away, making the amount of force he used excessive and leading to him falling into the room.

John was stretched out naked on his bed, reaching for Sherlock with his - tentacles. " _Homo Sapiens Tentaculigerous_. Of course." He only had three of the four major tentacles - two from his hips, as usual, but only one from his chest - the other must have been severely injured by the shoulder wound, or possibly was removed during surgery - the minor tentacles, arranged in pairs down his torso, all looked as usual, and were clearly undamaged since John was using them for the semi-traditional act of ripping apart Sherlock's clothes, which meant - "During the fertile period of your biennial cycle, I see," and John was pulling him over to the bed, which combined with his current state of mind meant that he considered Sherlock an acceptable choice of mate. "Honestly, you could have done better than to -" John wasn't paying attention to what he said, and his eyes were blank. This wasn't John choosing him, this was John's mind being overpowered by his instincts, and Sherlock was just the nearest warm body. "John? John? JOHN!"

John's eyes focussed, and he was looking at Sherlock again, seeing him as himself instead of just convenient. "Sherlock, you picked a really bad time to try and come in," he got out, but clearly part of him disagreed with his own statement, given that he had made no attempt to loosen his hold but instead was reaching behind Sherlock to press against his anus.

"Evidently." Not that Sherlock agreed, but it was evident that John felt his timing was off, and it would have been preferable to hold the necessary conversations about this before John was halfway delirious from need. He twisted in the way he'd theorised would - there, the tentacles released him as expected. Past discussions with so-called 'tentacle-bait' (during the period when he was living on the fringes of polite society in order to have better access to drugs) were proving more useful than he'd expected them to at the time. "Next time, you should mention this before I'm driven to try and knock your door down. And, please, ask. I believe it's considered polite to hold negotiations beforehand?" There, hopefully John would understand that this was Sherlock giving his consent, and not spend the next morning having a boring and entirely unnecessary guilt trip.

The tentacles were quite exciting, and Sherlock had high hopes (well, compared to his usual attitude) for the coming session.

John's "Ah," in response was uncertain, his body language veering between embarassed and needy. Sherlock rolled his eyes and intentionally rubbed one of John's tentacles against his penis - the texture was stimulating, and the action was hopefully sufficiently hard to misinterpret.

Clearly this was so, since John pulled him - 'yanked' might be the appropriate word - down and started thoroughly binding him. Sherlock smirked. "I've heard some -" John's remaining inhibitions had vanished, given how eagerly he was wrapping and squeezing - "truly fascinating stories about tentacle-sex during the fertile period -" again, talking to tentacle-bait had unanticipated rewards - "and I'm expecting this to be -" talking was proving surprisingly difficult as one tentacle slid inside him (not slimy, but the texture was unexpectedly slick, enabling it to enter with surprisingly little difficulty - high probability of there being some form of liquid excreted to ease the entry), and the tentacle now waiting in front of his mouth suggested that John wasn't interested in hearing him at the moment anyway - "John?" he asked, testing.

There was no response, but John's eyes were still aware - he wasn't blank, simply instinct-driven. Sherlock didn't resist as the tentacle slid inside his mouth (taste is much the same as any other skin; either excretion has no taste, or is not occurring since mouth provides own lubrication) and another entered his anus (tentacles are more yielding than most body-parts, making lack of stretching beforehand less problematic). John was clearly enjoying this as well; his eyes rolled back as he collapsed against the bed, tightening his hold on Sherlock (restriction unexpectedly pleasurable; possible unrecognised taste for bondage?) before forcing himself to look at Sherlock again (checking for enjoyment/approval).

He liked what he saw, if the sound he made was any indication. The tentacles inside Sherlock spasmed, a strange half-jerk that made him cry out in surprise, changing to pleasure as the tentacle around his penis somehow managed an undulating squeeze. He could just see John smiling as he twisted his tentacles again with more intent, opening him further before he was pulled into (the cowboy) position over John's groin.

Sherlock ran over the necessary facts in his mind. (Tentacanthropy is sexually transmitted. For the infected party to forget this fact is indicative of either lack of concern for others (untrue) or a strong desire for long-term connections to the person they are currently with.)

(Connection with John would prevent his [leaving] being kidnapped by Moriarty during next mating period.)

He lowered himself with an involuntary moan (length of time since last sexual encounter insufficient to cause degree of sensation; emotional involvement results in intensified reactions) which drove John to curse (unusual reaction, or only common during sexual activity? Requires further experimentation to determine) even as he thrust up, tentacles providing extra pressure just where Sherlock needed it (aim too perfect to be entirely instinctive; high likelihood of previous experience) -

Just once, Sherlock might have liked to be able to stop analysing everything -

He cried out for a final time, body tightening around John. John thrust up again, and then relaxed completely, tentacles retreating to their usual positions (reinforcing the ribcage and upper muscle layer). (Infection presumably successful; requirement for outside confirmation.) Sherlock stretched himself out, testing his muscles (unusually low degree of overstretching in lower body; due to tentacles, excretions, or other factors?) and asked, "So. I assume that you have successfully infected me with tentacanthropy?"

John froze, looking horrified. Sherlock forced down the impatient sigh that wanted to escape. "Honestly, John, don't tell me you didn't realise for yourself that it makes far more logical sense for the both of us to be infected. This way, there's no need to worry about Moriarty somehow arranging for your next pick-up to be one of his people, we can simply take care of each other. Much more efficient."

There. John wasn't entirely stupid; now that he'd had the logic explained to him, he should be able to follow it, and stop looking as though he'd just made a horrible mistake.

John did, but the expression of 'You're absolutely insane, do you know that?' wasn't a great improvement. "You got yourself infected intentionally."

"Yes."

"By me."

"Yes." John was having more difficulty with the logic than Sherlock had expected. Pity; he'd had such high hopes.

"Because it's _logical_?"

"Obviously. Does sex usually have this unfortunate effect upon your intelligence?" Sherlock sniped, wanting the conversation over and done with. It was boring and mundane, and he wasn't used to John being either.

"For - you didn't even know I was a tentacanthrope! Did you?"

That was uncalled for. Sherlock himself had told John that he always missed something. "Not until I saw the reason you'd hidden yourself away. I fail to see what that has to do with anything, however."

John rubbed at his forehead. (Good sign; usually signals his impending surrender.) "Why?"

Sherlock pushed himself up, wanting a better view of John's face. Maybe it would help him understand the difficulty John seemed to be having with this concept. It couldn't be that difficult to understand, surely? (Probability of sex stunting John's intellect growing. May need to choose between intelligent conversation and sex.) "I told you. It makes far more sense if we act as each other's mates, instead of you going off with other people chosen at random when your hormones overload your common sense."

John blinked at him. It seemed that something had finally registered with him. "You know, normal people just propose. Rings or something. Not, 'infect me so that it's more logical for us to be together'."

Sherlock snorted with relief, letting himself fall (no further need to read John's expression). "Boring," he dismissed. John stayed with him because he _wasn't_ boring; why would he want to change successful behaviour?

(Emotional attachment to society-advocated rituals? Need to observe facial cues.) "Do you want rings?"

John (finally) grinned at him. "I don't really think we need them by now, do we?"

Perfect.

(Risk of sentimentality overpowering John's own wishes - possible, but unlikely.)

(Test John's willingness to put up with [me] lack of comfort.)

Sherlock carefully arranged himself. The position had to be just comfortable enough for John to still fall asleep, but uncomfortable enough that doing so without asking Sherlock to move was evidence of sufficient emotional attachment to outweigh his discomfort.

John's only reaction was to mutter, half-asleep, "Don't know why I'm surprised, you've never done anything normal..."

***

Sherlock's biggest complaint about the next few days was the fact that John honestly believed that binning the card from Mycroft would somehow stop him being aware of it. He should have known better by now, surely?

(Mycroft's unannounced call when John was at the shops to check on his baby brother was entirely incidental to his knowledge of this. Really. And he had no idea what Mycroft was talking about when he suggested that interfering with the good doctor's sleeping habits was childish and likely to backfire. [He certainly wasn't going to stop now that Mycroft had told him to.]

Besides, John didn't seem to mind at all.)

Lestrade didn't even ask, which was probably just as well. Sherlock was surprised to learn just how hard it was to resist the urge to smack Anderson around the face with a tentacle, and though his coat covered any evidence of the changes to his body, it did start bulging oddly at times when he particularly wanted to slap the moron.

John caught his eye, once. It was the only time they started giggling before they even reached the crime scene.

Overall, there were no major changes to their lives together.

[Except that Sherlock could feel a little more secure that John wasn't going to leave him.]


End file.
